| Popis: |
Equilibrium molecular dynamics (EMD) simulations are used to model density ρL, dynamic viscosity ηL, and self-diffusivity Dself of liquid ethane at pressures close to saturation conditions and temperatures T between (184–298) K, close to the critical temperature Tc. To correct for a T-dependent drift of the simulated results from experimental data, a T-dependent force field modification from our previous studies is extended to a wider T-range. The modification is validated within this work by comparing predicted ρL, ηL, and Dself to experimental reference data. With the modification applied, EMD simulations are able to predict ρL, ηL, and Dself of liquid ethane at T = 298 K with relative deviations of 6.3%, 13%, and 28% from literature references, respectively. Simulations of binary mixtures of liquid ethane with different dissolved gases were performed to predict the Fick diffusivity D11. At a mole fraction of dissolved nitrogen xN2 = 0.03, a deviation of more than a factor of three is found between simulation results and experimental results determined using the dynamic light scattering method. This shows that EMD simulations are not able to predict the critical slowing down of D11 approaching Tc, despite excellent agreement between simulations and reference data for neat ethane. |
